Power transmission device

ABSTRACT

A power transmission device, includes a motor; a gear mechanism connected downstream of the motor; a drive shaft connected downstream of the gear mechanism and disposed passing through an inner periphery of the motor; a pump that sucks oil through a pump inlet; and a plate that includes a facing surface facing the gear mechanism in an axial direction. The pump inlet is disposed adjacent to the plate on a back surface side of the facing surface.

TECHNICAL FIELD

The present invention relates to a power transmission device.

BACKGROUND ART

Patent Literature 1 discloses a power transmission device for anelectric vehicle. The power transmission device includes a gearmechanism (a planetary reduction gear and a differential mechanism).

A strainer that filters oil to be supplied to the gear mechanism andsupplies the oil to an oil pump is disposed on an outer peripheral side(an outer side in the radial direction) of the gear mechanism.

CITATION LIST Patent Literature

Patent Literature 1: JP2019-152320A

SUMMARY OF INVENTION Problems to be Solved by the Invention

As the gear mechanism rotates, the oil on the outer peripheral side ofthe gear mechanism is scraped up, and the amount of oil near a suctionport of the strainer may decrease. When the oil pump sucks oil when theamount of the oil near the suction port decreases, air may be sucked.

In the power transmission device, it is required to reduce the airsuction of the oil pump.

Means to Solve Problem

According to an aspect of the present invention, a power transmissiondevice, includes:

-   -   a motor;    -   a gear mechanism connected downstream of the motor;    -   a drive shaft connected downstream of the gear mechanism and        disposed passing through an inner periphery of the motor;    -   a pump that sucks oil through a pump inlet; and    -   a plate that includes a facing surface facing the gear mechanism        in an axial direction.

The pump inlet is disposed adjacent to the plate on a back surface sideof the facing surface.

Effects of Invention

According to one aspect of the present invention, it is possible toreduce the air suction of the oil pump.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a skeleton diagram of a power transmission device according toan embodiment.

FIG. 2 is a schematic cross-sectional view of the power transmissiondevice.

FIG. 3 is an enlarged view around a planetary reduction gear of thepower transmission device.

FIG. 4 is an enlarged view around a differential mechanism of the powertransmission device.

FIG. 5 is an exploded perspective view of the differential mechanism ofthe power transmission device.

FIG. 6 is a diagram illustrating an oil catch portion.

FIG. 7 is a diagram illustrating the oil catch portion.

FIG. 8 is a diagram illustrating the oil catch portion.

FIG. 9 is a diagram illustrating the oil catch portion.

FIG. 10 is a diagram illustrating the oil catch portion.

FIG. 11 is a diagram illustrating the oil catch portion.

FIG. 12 is a diagram illustrating a plate member.

FIG. 13 is a diagram illustrating the plate member.

FIG. 14 is a diagram of a fourth box viewed from a motor side.

FIG. 15 is a diagram of the fourth box viewed from the motor side.

FIG. 16 is a diagram illustrating a park lock mechanism.

FIG. 17 is a diagram illustrating the park lock mechanism.

FIG. 18 is a diagram illustrating the park lock mechanism.

FIG. 19 is an enlarged view around a strainer below a main body box.

FIG. 20 is a schematic diagram showing disposition of the strainer whenthe main body box is viewed from above in a vertical direction.

FIG. 21 is a diagram showing disposition of a strainer according toModification 1.

FIG. 22 is a schematic diagram showing disposition of the strainer whenthe main body box is viewed from above in the vertical direction.

FIG. 23 is a schematic diagram showing disposition of a straineraccording to Modification 2.

FIG. 24 is a diagram showing a configuration example of an oil pumpaccording to Modification 3.

FIG. 25 is a diagram showing a configuration example of the oil pumpaccording to Modification 3.

FIG. 26 is a diagram showing a configuration example of the oil pumpaccording to Modification 3.

DESCRIPTION OF EMBODIMENTS

Hereinafter, a power transmission device according to an embodiment ofthe present invention.

In the following description, when referring to a second element(member, portion, or the like) connected to a first element (member,portion, or the like), a second element (member, portion, or the like)connected downstream of a first element (member, portion, or the like),or a second element (member, portion, or the like) connected upstream ofa first element (member, portion, or the like), it is meant that thefirst element and the second element are connected to each other in apower-transmissible manner. A power input side is upstream, and a poweroutput side is downstream. The first element and the second element maybe connected to each other via another element (a clutch, other gearmechanisms, or the like).

“Overlapping when viewed from a predetermined direction” means that aplurality of elements are arranged in a predetermined direction, and hasthe same meaning as “overlapping in a predetermined direction”. The“predetermined direction” is, for example, an axial direction, a radialdirection, a gravitational direction, or a vehicle running direction(vehicle forward direction, vehicle rearward direction).

If a drawing shows that a plurality of elements (member, portion, or thelike) are arranged in a predetermined direction, it can be consideredthat in explanation of the description, there is a sentence explainingthat the plurality of elements overlap when viewed from thepredetermined direction.

“Not overlapping when viewed from a predetermined direction” and “offsetwhen viewed from a predetermined direction” mean that a plurality ofelements are not arranged in a predetermined direction, and has the samemeaning as “not overlapping in a predetermined direction” and “offset ina predetermined direction”. The “predetermined direction” is, forexample, an axial direction, a radial direction, a gravitationaldirection, or a vehicle running direction (vehicle forward direction,vehicle rearward direction).

If a drawing shows that a plurality of elements (member, portion, or thelike) are not arranged in a predetermined direction, it can beconsidered that in explanation of the description, there is a sentenceexplaining that the plurality of elements do not overlap when viewedfrom the predetermined direction.

“When viewed from a predetermined direction, a first element (member,portion, or the like) is positioned between a second element (member,portion, or the like) and a third element (member, portion, or thelike)” means that the first element can be observed to be between thesecond element and the third element. The “predetermined direction” is,for example, an axial direction, a radial direction, a gravitationaldirection, or a vehicle running direction (vehicle forward direction,vehicle rearward direction).

For example, when the second element, the first element, and the thirdelement are arranged in this order along the axial direction, it can besaid that the first element is positioned between the second element andthe third element when viewed from the radial direction. If a drawingshows that a first element is between a second element and a thirdelement when viewed from a predetermined direction, it can be consideredthat in explanation of the description, there is a sentence explainingthat the first element is between the second element and the thirdelement.

When two elements (member, portion, or the like) overlap when viewedfrom the axial direction, the two elements are coaxial.

The “axial direction” means an axial direction of a rotation axis of amember that constitutes the power transmission device. The “radialdirection” means a direction orthogonal to the rotation axis of themember that constitutes the power transmission device. The member is,for example, a motor, a gear mechanism, or a differential gearmechanism.

FIG. 1 is a skeleton diagram illustrating the power transmission device1 according to the present embodiment.

FIG. 2 is a schematic cross-sectional view illustrating the powertransmission device 1 according to the present embodiment.

FIG. 3 is an enlarged view around a planetary reduction gear 4 of thepower transmission device 1.

FIG. 4 is an enlarged view around a differential mechanism 5 of thepower transmission device 1.

As shown in FIG. 1 , a power transmission device 1 includes a motor 2, aplanetary reduction gear 4 (reduction mechanism) that decelerates outputrotation of the motor 2 and then inputs the decelerated output rotationto a differential mechanism 5 (differential gear), drive shafts DA andDB, and a park lock mechanism 3. The planetary reduction gear 4 and thedifferential mechanism 5 constitute a gear mechanism.

In the power transmission device 1, the park lock mechanism 3, theplanetary reduction gear 4, the differential mechanism 5, and the driveshafts DA and DB (drive shaft) are arranged along a transmission path ofthe output rotation of the motor 2 around the rotation axis X.

In the power transmission device 1, the output rotation of the motor 2is decelerated by the planetary reduction gear 4 and then input to thedifferential mechanism 5, and then transmitted through the drive shaftsDA and DB to left and right driving wheels W and W of a vehicle on whichthe power transmission device 1 is mounted.

Here, the planetary reduction gear 4 is connected downstream of themotor 2, the differential mechanism 5 is connected downstream of theplanetary reduction gear 4, and the drive shafts DA and DB are connecteddownstream of the differential mechanism 5.

As shown in FIG. 2 , a main body box 10 (box) of the power transmissiondevice 1 includes a first box 11 that accommodates the motor 2 and asecond box 12 that is externally inserted into the first box 11. Themain body box 10 includes a third box 13 assembled to the first box 11and a fourth box 14 assembled to the second box 12.

The first box 11 includes a cylindrical support wall portion 111, and aflange-like joint portion 112 formed at one end 111 a of the supportwall portion 111.

The first box 11 is disposed with the support wall portion 111 orientedalong a rotation axis X of the motor 2, and the motor 2 is accommodatedon an inner side of the support wall portion 111.

The joint portion 112 is provided in a direction orthogonal to therotation axis X and formed with an outer diameter larger than that ofthe support wall portion 111.

The second box 12 includes a cylindrical peripheral wall portion 121, aflange-shaped joint portion 122 provided at one end 121 a of theperipheral wall portion 121, and a flange-shaped joint portion 123provided at the other end 121 b of the peripheral wall portion 121.

The peripheral wall portion 121 is formed with an inner diameter thatallows the peripheral wall portion 121 to be externally inserted intothe support wall portion 111 of the first box 11.

The first box 11 and the second box 12 are assembled to each other suchthat the peripheral wall portion 121 of the second box 12 is externallyinserted into the support wall portion 111 of the first box 11.

The joint portion 122 on the one end 121 a side of the peripheral wallportion 121 comes into contact with the joint portion 112 of the firstbox 11 from the rotation axis X direction. These joint portions 122 and112 are connected to each other by bolts (not shown).

In the first box 11, a plurality of grooves 111 b are provided on anouter periphery of the support wall portion 111. The plurality ofgrooves 111 b are provided at intervals in the rotation axis Xdirection. The grooves 111 b are provided over an entire circumferencein a circumferential direction around the rotation axis X.

The peripheral wall portion 121 of the second box 12 is externallyinserted into the support wall portion 111 of the first box 11. Theperipheral wall portion 121 closes openings of the grooves 111 b. Aplurality of cooling paths CP through which a coolant CL flows areformed between the support wall portion 111 and the peripheral wallportion 121.

The peripheral wall portion 121 is provided with an inlet 124 a for thecoolant CL on the joint portion 122 side, and an outlet 124 b for thecoolant CL on the joint portion 123 side. The inlet 124 a and the outlet124 b are holes penetrating the peripheral wall portion 121 in theradial direction of the rotation axis X, and are connected to pipes (notshown) through which the coolant CL flows. The coolant CL is circulatedthrough a pipe (not shown) provided inside the vehicle by a water pump(not shown). The coolant CL is introduced into the cooling path CP fromthe inlet 124 a, and cools oil OL inside a motor chamber Sa, which willbe described later.

Ring grooves 111 c and 111 c are formed on both sides of a region inwhich the concave grooves 111 b are provided on an outer periphery ofthe support wall portion 111 of the first box 11. Seal rings 113 and 113are externally fitted to the ring grooves 111 c and 111 c.

These seal rings 113 are pressed against an inner periphery of theperipheral wall portion 121 that is externally inserted to the supportwall portion 111 to seal a gap between the outer periphery of thesupport wall portion 111 and the inner periphery of the peripheral wallportion 121.

A beam portion 120 extending toward an inner diameter side from thejoint portion 123 is provided at the other end 121 b of the second box12. The beam portion 120 is oriented in a direction orthogonal to therotation axis X. An opening 120 a through which the drive shaft DA isinserted is provided in a region of the beam portion 120 that intersectswith the rotation axis X.

A tubular motor support portion 125 surrounding the opening 120 a isprovided on a surface of the beam portion 120 on the motor 2 side (onthe right side in the drawing).

The motor support portion 125 is inserted inside a coil end 253 b, whichwill be described later. The motor support portion 125 faces an endportion 21 b of a rotor core 21 with a gap in the rotation axis Xdirection.

A bearing B1 is supported on an inner periphery of the motor supportportion 125. An outer periphery of a motor shaft 20 is supported by themotor support portion 125 via the bearing B1.

A plurality of openings 120 b extending in the radial direction of therotation axis X are formed between the motor support portion 125 and thejoint portion 123. The plurality of openings 120 b are provided atintervals in a circumferential direction of the rotation axis X. Thesecond box 12 and the fourth box 14 internally communicate with eachother through the openings 120 b.

In FIG. 2 , a vertical direction with respect to a mounting state of thepower transmission device 1 on the vehicle is illustrated as an up-downdirection in the drawing. A lower region in the vertical direction ofthe peripheral wall portion 121 of the second box 12 has a largerthickness in the radial direction than that of an upper region.

An oil reservoir portion 128 is provided on the region having the largerthickness in the radial direction, penetrating in the rotation axis Xdirection.

The oil reservoir portion 128 communicates with an axial oil passage 138provided in a joint portion 132 of the third box 13 via a communicationhole 112 a provided in the joint portion 112 of the first box 11.

The third box 13 includes a wall portion 130 orthogonal to the rotationaxis X. The joint portion 132 having a ring shape when viewed from therotation axis X direction is provided on an outer peripheral portion ofthe wall portion 130.

As viewed from the first box 11, the third box 13 is positioned on aside opposite to the differential mechanism 5 (on the right side in thedrawing). The joint portion 132 of the third box 13 is joined to thejoint portion 112 of the first box 11 from the rotation axis Xdirection. The third box 13 and the first box 11 are connected to eachother with bolts (not shown). In this state, the third box 13 closes theopening on the joint portion 122 side (the right side in the drawing) ofthe support wall portion 111 of the first box 11.

In the third box 13, an insertion hole 130 a for the drive shaft DA isprovided in a central portion of the wall portion 130.

A lip seal RS is fixed to an inner periphery of the insertion hole 130a. The lip seal RS brings a lip portion (not shown) into elastic contactwith an outer periphery of the drive shaft DA. A gap between the innerperiphery of the insertion hole 130 a and the outer periphery of thedrive shaft DA is sealed with the lip seal RS.

A peripheral wall portion 131 surrounding the insertion hole 130 a isprovided on a surface of the wall portion 130 on the first box 11 side(the left side in the drawing). The drive shaft DA is supported on theinner periphery of the peripheral wall portion 131 via a bearing B4.

A motor support portion 135 is disposed on the motor 2 side (the leftside in the drawing) when viewed from the peripheral wall portion 131.The motor support portion 135 has a tubular shape surrounding therotation axis X with a gap therebetween.

A cylindrical connection wall 136 is connected to an outer periphery ofthe motor support portion 135. The connection wall 136 is formed with alarger outer diameter than the peripheral wall portion 131 on the wallportion 130 side (the right side in the drawing). The connection wall136 is provided along the rotation axis X in a direction away from themotor 2. The connection wall 136 connects the motor support portion 135to the wall portion 130 of the third box 13.

The motor support portion 135 is supported by the third box 13 via theconnection wall 136. One end 20 a side of the motor shaft 20 penetratesan inner side of the motor support portion 135 from the motor 2 side tothe peripheral wall portion 131 side.

The bearing B1 is supported on an inner periphery of the motor supportportion 135. An outer periphery of the motor shaft 20 is supported bythe motor support portion 135 via the bearing B1.

The connection wall 136 is provided with an opening 136 a. A space(internal space Sc) surrounded by the connection wall 136 communicateswith the motor chamber Sa, which will be described later, through thisopening 136 a.

The fourth box 14 includes a peripheral wall portion 141 surrounding theouter periphery of the planetary reduction gear 4 and the differentialmechanism 5, and a flange-shaped joint portion 142 formed on an endportion of the peripheral wall portion 141 on the second box 12 side.

The fourth box 14 is positioned on the differential mechanism 5 side(the left side in the drawing) when viewed from the second box 12. Thejoint portion 142 of the fourth box 14 is joined to the joint portion123 of the second box 12 from the rotation axis X direction. The fourthbox 14 and the second box 12 are connected to each other with bolts (notshown).

Inside the main body box 10 of the power transmission device 1, themotor chamber Sa that accommodates the motor 2 and a gear chamber Sbthat accommodates the planetary reduction gear 4 and the differentialmechanism 5 are formed.

The motor chamber Sa is formed within the first box 11 between the beamportion 120 of the second box 12 and the wall portion 130 of the thirdbox 13.

The gear chamber Sb is formed within the fourth box 14 and between thebeam portion 120 of the second box 12 and the peripheral wall portion141 of the fourth box 14. The motor chamber Sa and the gear chamber Sbcommunicate with each other through the opening 120 b of the beamportion 120. The main body box 10 contains the oil OL for lubricatingthe motor 2, the planetary reduction gear 4, the differential mechanism5, and the like. As indicated by a thick line in FIG. 2 , the motorchamber Sa and the gear chamber Sb are provided with an oil storageportion OP that stores the oil OL. The oil OL in the oil storage portionOP can also flow into the internal space Sc through the opening 136 a.

A plate member 8 (plate) is provided inside the gear chamber Sb.

The plate member 8 is fixed with bolts B to the fourth box 14.

The plate member 8 divides the gear chamber Sb into a first gear chamberSb1 that accommodates the planetary reduction gear 4 and thedifferential mechanism 5, and a second gear chamber Sb2 thataccommodates the park lock mechanism 3.

The second gear chamber Sb2 is positioned between the first gear chamberSb1 and the motor chamber Sa in the rotation axis X direction. The motorchamber Sa and the second gear chamber Sb2 communicate with each otherthrough the opening 120 b of the beam portion 120.

The motor 2 includes the motor shaft 20, the rotor core 21 (rotor), anda stator core 25 (stator). The motor shaft 20 is cylindrical. The driveshaft DA is disposed passing through the inner periphery of the motorshaft 20. The rotor core 21 is cylindrical and is externally insertedinto the motor shaft 20. The stator core 25 is a fixed body positionedoutside the rotor core 21 in the radial direction. The stator core 25surrounds the outer periphery of the rotor core 21 with a gaptherebetween.

In the motor shaft 20, the bearings B1 and B1 are externally insertedand fixed to both sides of the rotor core 21, respectively.

The bearing B1 positioned on the one end 20 a side (the right side inthe drawing) of the motor shaft 20 when viewed from the rotor core 21 issupported on the inner periphery of the motor support portion 135 of thethird box 13. The bearing B1 positioned on the other end 20 b side issupported on the inner periphery of the cylindrical motor supportportion 125 of the second box 12.

The motor support portions 135 and 125 are respectively disposed facingthe one end portion 21 a and the other end portion 21 b of the rotorcore 21, with a gap in the rotation axis X direction therebetween, onthe inner diameter side of the coil ends 253 a and 253 b, which will bedescribed later.

The rotor core 21 is formed by laminating a plurality of silicon steelplates. Each of the silicon steel plates is externally inserted into themotor shaft 20 in a state where relative rotation thereof with the motorshaft 20 is restricted.

The silicon steel plate has a ring shape when viewed from the rotationaxis X direction of the motor shaft 20. N-pole and S-pole magnets (notshown) are provided alternately in a circumferential direction aroundthe rotation axis X on the outer peripheral side of the silicon steelplate.

The stator core 25 surrounding the outer periphery of the rotor core 21is formed by laminating a plurality of electromagnetic steel plates. Thestator core 25 is fixed to the inner periphery of the cylindricalsupport wall portion 111 of the first box 11.

Each of the electromagnetic steel plates includes a yoke portion 251, ateeth portion 252, and a coil 253. The yoke portion 251 is ring-shapedand fixed to the inner periphery of the support wall portion 111. Theteeth portion 252 protrudes from the inner periphery of the yoke portion251 toward the rotor core 21 side.

The coil 253 is formed by winding a wire (not shown) over a plurality ofthe teeth portions 252. A known copper wire or the like can be used asthe wire that forms the coil 253. Note that the coil 253 may have aconfiguration in which the wire is distributedly wound around each ofthe plurality of teeth portions 252 protruding toward the rotor core 21side, or may have a configuration in which the wire is concentratedlywound.

In the stator core 25, a length in the rotation axis X direction of thecoil 253 is set to be longer than that of the rotor core 21. In thestator core 25, coil ends 253 a and 253 b positioned at both endportions of the coil 253 in the rotation axis X direction protrude fromthe rotor core 21 in the rotation axis X direction. The coil ends 253 aand 253 b have a symmetrical shape with the teeth portions 252interposed therebetween.

The other end 20 b side of the motor shaft 20 passes through the opening120 a provided in the beam portion 120 (motor support portion 125) ofthe second box 12 to the differential mechanism 5 side (the left side inthe drawing) and is positioned inside the fourth box 14.

The other end 20 b of the motor shaft 20 faces a side gear 54A, whichwill be described later, inside the fourth box 14 with a gap in therotation axis X direction therebetween.

As shown in FIG. 3 , the motor shaft 20 is provided with a steppedportion 201 in a region positioned inside the fourth box 14. In themotor shaft 20, a region from the stepped portion 201 to the vicinity ofthe other end 20 b serves as a fitting portion 202 provided with aspline on an outer periphery thereof.

A park gear 30 of the park lock mechanism 3 and a sun gear 41 arespline-fitted to an outer periphery of the fitting portion 202.

One side surface of the park gear 30 in the rotation axis X direction isin contact with the stepped portion 201. One end 410 a of a cylindricalbase portion 410 of the sun gear 41 is in contact with the other sidesurface of the park gear 30 in the rotation axis X direction.

A nut N screwed onto the other end 20 b of the motor shaft 20 is pressedagainst the other end 410 b of the base portion 410 from the rotationaxis X direction.

The sun gear 41 and the park gear 30 are interposed between the nut Nand the stepped portion 201 so as not to rotate relative to the motorshaft 20.

The sun gear 41 includes a teeth portion 411 on the outer periphery ofthe motor shaft 20 on the other end 20 b side. A large-diameter gearportion 431 of a stepped pinion gear 43 meshes with an outer peripheryof the teeth portion 411.

The stepped pinion gear 43 includes the large-diameter gear portion 431that meshes with the sun gear 41 and a small-diameter gear portion 432having a smaller diameter than the large-diameter gear portion 431.

The stepped pinion gear 43 is a gear component in which thelarge-diameter gear portion 431 and the small-diameter gear portion 432are arranged in an axis line X1 direction parallel to the rotation axisX and integrally provided.

The large-diameter gear portion 431 is formed with an outer diameter R1larger than an outer diameter R2 of the small-diameter gear portion 432.

The stepped pinion gear 43 is oriented along the axis line X1. Thelarge-diameter gear portion 431 of the stepped pinion gear 43 ispositioned on the motor 2 side (the right side in the drawing).

An outer periphery of the small-diameter gear portion 432 meshes with aninner periphery of a ring gear 42. The ring gear 42 has a ring shapesurrounding the rotation axis X with a gap therebetween. A plurality ofengaging teeth 421 protruding outward in the radial direction areprovided on an outer periphery of the ring gear 42. The plurality ofengaging teeth 421 are provided around the rotation axis X in thecircumferential direction at intervals.

The engaging teeth 421 provided on the outer periphery of the ring gear42 are spline-fitted to teeth portions 146a provided on a support wallportion 146 of the fourth box 14. Rotation of the ring gear 42 aroundthe rotation axis X is restricted.

The stepped pinion gear 43 includes a through hole 430 penetrating innerdiameter sides of the large-diameter gear portion 431 and thesmall-diameter gear portion 432 in the axis line X1 direction.

The stepped pinion gear 43 is rotatably supported via needle bearings NBand NB on an outer periphery of a pinion shaft 44 passing through thethrough hole 430.

As shown in FIG. 4 , an in-shaft oil passage 440 is provided inside thepinion shaft 44. The in-shaft oil passage 440 penetrates from one end 44a of the pinion shaft 44 to the other end 44 b along the axis line X1.The pinion shaft 44 is provided with oil holes 442 and 443 that allowthe in-shaft oil passage 440 and the outer periphery of the pinion shaft44 to communicate with each other.

Furthermore, the pinion shaft 44 is provided with an introductionpassage 441 for introducing the oil OL into the in-shaft oil passage440. The introduction passage 441 communicates with an in-case oilpassage 781 formed in a base portion 71 of a second case portion 7,which will be described later.

The oil OL scraped up by a differential case 50, which will be describedlater, flows into the in-case oil passage 781. The oil OL that moves tothe outer diameter side in the radial direction due to a centrifugalforce generated by rotation of the differential case 50 flows into thein-case oil passage 781.

The oil OL that flows from the in-case oil passage 781 into theintroduction passage 441 flows into the in-shaft oil passage 440 of thepinion shaft 44. The oil OL that flows into the in-shaft oil passage 440is discharged outward in the radial direction through the oil holes 442and 443. The oil OL discharged from the oil holes 442 and 443 lubricatesthe needle bearing NB externally inserted into the pinion shaft 44.

The pinion shaft 44 is provided with a through hole 444 on the other end44 b side with respect to a region where the introduction passage 441 isprovided. The through hole 444 penetrates the pinion shaft 44 in adiametrical direction.

The pinion shaft 44 is provided such that the through hole 444 and aninsertion hole 782 on the second case portion 7 side, which will bedescribed later, are aligned with each other around the axis line X1 inphase. A positioning pin P inserted into the insertion hole 782 passesthrough the through hole 444 of the pinion shaft 44. As a result, thepinion shaft 44 is supported on the second case portion 7 side whilerotation thereof around the axis line X1 is restricted.

As shown in FIG. 4 , on the one end 44 a side in a longitudinaldirection of the pinion shaft 44, a region that protrudes from thestepped pinion gear 43 serves as a first shaft portion 445. The firstshaft portion 445 is supported by a support hole 61 a provided in afirst case portion 6 of the differential case 50.

On the other end 44 b side in the longitudinal direction of the pinionshaft 44, a region that protrudes from the stepped pinion gear 43 servesas a second shaft portion 446. The second shaft portion 446 is supportedby a support hole 71 a provided in a second case portion 7 of thedifferential case 50.

Here, the first shaft portion 445 means a region on the one end 44 aside of the pinion shaft 44 where the stepped pinion gear 43 is notexternally inserted. The second shaft portion 446 means a region on theother end 44 b side of the pinion shaft 44 where the stepped pinion gear43 is not externally inserted.

A length of the second shaft portion 446 of the pinion shaft 44 in theaxis line X1 direction is longer than a length of the first shaftportion 445 in the axis line X1 direction.

A main configuration of the differential mechanism 5 will be describedbelow.

FIG. 5 is an exploded perspective view of the differential mechanism 5.

As shown in FIGS. 4 and 5 , the differential case 50 of the differentialmechanism 5 is formed by assembling the first case portion 6 and thesecond case portion 7 in the rotation axis X direction. In the presentembodiment, the first case portion 6 and the second case portion 7 ofthe differential case 50 function as carriers that support the pinionshaft 44 of the planetary reduction gear 4.

Three pinion mate gears 52 and three pinion mate shafts 51 are providedbetween the first case portion 6 and the second case portion 7 of thedifferential case 50. The pinion mate shaft 51 functions as a supportshaft that supports the pinion mate gear 52.

The pinion mate shafts 51 are provided at equal intervals in thecircumferential direction around the rotation axis X. An end portion onthe inner diameter side of each of the pinion mate shafts 51 isconnected to a common connecting portion 510 with each other.

The pinion mate gears 52 are externally inserted into the pinion mateshafts 51, respectively. Each of the pinion mate gears 52 is in contactwith the connecting portion 510 from an outer side of the rotation axisX in the radial direction.

In this state, the pinion mate gears 52 are rotatably supported by thepinion mate shafts 51, respectively.

As shown in FIG. 4 , in the differential case 50, a side gear 54A ispositioned on one side of the connecting portion 510 in the rotationaxis X direction, and a side gear 54B is positioned on the other side.The side gear 54A is rotatably supported by a first case portion 6. Theside gear 54B is rotatably supported by the second case portion 7.

The side gear 54A meshes with a pinion mate gear 52 from one side in therotation axis X direction. The side gear 54B meshes with the pinion mategear 52 from the other side in the rotation axis X direction.

The first case portion 6 includes a ring-shaped base portion 61. Anopening 60 is provided in a central portion of the base portion 61. Acylindrical wall portion 611 surrounding the opening 60 is provided on asurface of the base portion 61 opposite to the second case portion 7(the right side in the drawing). An outer periphery of the cylindricalwall portion 611 is supported by the plate member 8 via a bearing B3.

As shown in FIG. 5 , a surface of the base portion 61 on the second caseportion 7 side is provided with three connecting beams 62 extendingtoward the second case portion 7 side.

The connecting beams 62 are provided at equal intervals in thecircumferential direction around the rotation axis X. The connectingbeam 62 includes a base portion 63 orthogonal to the base portion 61 anda connecting portion 64 wider than the base portion 63.

As shown in FIG. 4 , a support groove 65 for supporting the pinion mateshaft 51 is provided on a tip surface of the connecting portion 64.

An arc portion 641 is formed along an outer periphery of the pinion mategear 52 on the inner diameter side (the rotation axis X side) of theconnecting portion 64. The arc portion 641 supports the outer peripheryof the pinion mate gear 52.

A gear support portion 66 is connected to a boundary portion between thebase portion 63 and the connecting portion 64 of the connecting beam 62.The gear support portion 66 is oriented in a direction orthogonal to therotation axis X. The gear support portion 66 includes a through hole 660in a central portion thereof. This through hole 660 is externallyinserted into a tubular wall 541 of the side gear 54A.

The base portion 61 is provided with a support hole 61 a. The one end 44a of the pinion shaft 44 is externally inserted into the support hole 61a.

The second case portion 7 includes a ring-shaped base portion 71.

A through hole 70 penetrating through the base portion 71 in a thicknessdirection is provided in a central portion of the base portion 71.

A cylindrical wall portion 72 surrounding the through hole 70 and aperipheral wall portion 73 surrounding the cylindrical wall portion 72with a gap therebetween are provided on a surface of the base portion 71opposite to the first case portion 6 (the left side in the drawing).

Slits 710 that penetrate the base portion 71 in the thickness directionare provided on an inner diameter side of the peripheral wall portion73. Between the slits 710 and 710 adjacent to each other in thecircumferential direction around the rotation axis, a protruding wall711 is provided. The protruding wall 711 extends linearly in the radialdirection of the rotation axis X. The protruding wall 711 is providedstraddling the peripheral wall portion 73 on the outer diameter side andthe cylindrical wall portion 72 on the inner diameter side.

On an outer diameter side of the peripheral wall portion 73, between thesupport holes 71 a and 71 a adjacent to each other in thecircumferential direction around the rotation axis X, bolt accommodatingportions 76 and 76 recessed toward a back side of paper surface areprovided.

An insertion hole 77 for a bolt is opened inside the bolt accommodatingportion 76. The insertion hole 77 penetrates the base portion 71 in thethickness direction (the rotation axis X direction).

Connecting portions 74 protruding toward the first case portion 6 areprovided on a surface of the base portion 71 on the first case portion 6side (the right side in the drawing).

As shown in FIG. 4 , a support groove 75 for supporting the pinion mateshaft 51 is provided on a tip surface of the connecting portion 74. Anarc portion 741 along the outer periphery of the pinion mate gear 52 isprovided on the inner diameter side (the rotation axis X side) of theconnecting portion 74. The arc portion 741 supports the outer peripheryof the pinion mate gear 52.

As shown in FIG. 5 , a cylindrical wall portion 540 is provided on theback surface of the side gear 54B. The washer 55 is externally insertedinto the cylindrical wall portion 540. The base portion 71 of the secondcase portion 7 is provided with a guide portion 78 protruding toward thefirst case portion 6 (the right side in the drawing).

As shown in FIG. 4 , the pinion shaft 44 is inserted into the supporthole 71 a of the guide portion 78 from the first case portion 6 side ina cross-sectional view along the axis line X1.

In the differential case 50, a bearing B2 is externally inserted intothe cylindrical wall portion 72 of the second case portion 7. Thebearing B2 externally inserted into the cylindrical wall portion 72 isheld by a support portion 145 of the fourth box 14, and the cylindricalwall portion 72 of the differential case 50 is rotatably supported bythe fourth box 14 via the bearing B2.

The drive shaft DB passing through an opening portion 145 a of thefourth box 14 is inserted into the support portion 145 from the rotationaxis X direction. The drive shaft DB is rotatably supported by thesupport portion 145.

The lip seal RS is fixed to an inner periphery of the opening portion145 a. A lip portion (not shown) of the lip seal RS is in elasticcontact with an outer periphery of the cylindrical wall portion 540 ofthe side gear 54B externally inserted into the drive shaft DB. As aresult, a gap between an outer periphery of the cylindrical wall portion540 of the side gear 54B and an inner periphery of the opening portion145 a is sealed.

The first case portion 6 of the differential case 50 is supported by theplate member 8 via the bearing B3 externally inserted into thecylindrical wall portion 611.

As shown in FIG. 2 , the drive shaft DA passing through the insertionhole 130 a of the third box 13 is inserted into the first case portion 6from the rotation axis direction.

The drive shaft DA is provided across the inner diameter side of themotor shaft 20 of the motor 2 and the sun gear 41 of the planetaryreduction gear 4 in the rotation axis X direction.

As shown in FIG. 4 , inside the differential case 50, the side gears 54Aand 54B are spline-fitted to an outer periphery of a tip portion of thedrive shafts DA and DB. The side gears 54A, 54B and the drive shafts DA,DB are connected to each other in a manner of rotating together aroundthe rotation axis X.

In this state, the side gears 54A and 54B are arranged opposite to eachother with a gap therebetween in the rotation axis X direction. Aconnecting portion 510 of the pinion mate shaft 51 is positioned betweenthe side gears 54A and 54B.

As shown in FIG. 5 , the pinion mate gear 52 is supported by each of thepinion mate shafts 51. The pinion mate gears 52 are assembled to theside gear 54A positioned on one side in the rotation axis X directionand the side gear 54B positioned on the other side in such a manner thatthe teeth portions thereof are meshed with each other.

As shown in FIG. 2 , when the power transmission device 1 is mounted onthe vehicle, a lower portion of the differential case 50 is positionedinside the oil storage portion OP.

In the present embodiment, the oil OL is stored up to a height where theconnecting beam 62 is positioned within the oil storage portion OP whenthe connecting beam 62 is positioned at the lowest position.

The oil OL in the oil storage portion OP is scraped up by thedifferential case 50 rotating around the rotation axis X when the outputrotation of the motor 2 is transmitted.

FIGS. 6 to 11 are diagrams illustrating an oil catch portion 15.

FIG. 6 is a plan view of the fourth box 14 viewed from the third box 13side.

FIG. 7 is a perspective view of the oil catch portion 15 shown in FIG. 6as viewed obliquely from above.

FIG. 8 is a plan view of the fourth box 14 viewed from the third box 13side. FIG. 8 shows a state in which the differential case 50 isdisposed. FIG. 9 is a perspective view of the oil catch portion 15 shownin FIG. 8 as viewed obliquely from above.

FIG. 10 is a schematic diagram of an A-A cross section in FIG. 8 .

FIG. 11 is a schematic diagram illustrating a positional relationbetween the oil catch portion 15 and the differential case 50 (the firstcase portion 6 and the second case portion 7) when the powertransmission device 1 is viewed from above.

Note that in FIGS. 6 and 8 , hatching is added to clarify the positionsof the joint portion 142 of the fourth box 14 and the support wallportion 146. In FIGS. 6 and 8 , illustration of the plate member 8 isomitted.

As shown in FIG. 6 , the fourth box 14 is provided with the support wallportion 146 surrounding the central opening portion 145 a with a gaptherebetween when viewed from the rotation axis X direction. The innerside (rotation axis X) of the support wall portion 146 serves as anaccommodation portion 140 of the differential case 50.

A space for the oil catch portion 15 and a space for a breather chamber16 are formed in an upper portion of the fourth box 14.

The support wall portion 146 of the fourth box 14 is provided with acommunication port 147 in a region intersecting with the vertical lineVL. The communication port 147 allows the oil catch portion 15 and theaccommodation portion 140 of the differential case 50 to communicatewith each other.

The oil catch portion 15 and the breather chamber 16 are respectivelypositioned on one side (the left side in the drawing) and the other side(the right side in the drawing) interposing the vertical line VLorthogonal to the rotation axis X.

The oil catch portion 15 is disposed at a position offset from thevertical line VL passing through a rotation center (rotation axis X) ofthe differential case 50. When the oil catch portion 15 is viewed fromabove, the oil catch portion 15 is disposed at a position offset fromright above the differential case 50.

Here, the vertical line VL is a vertical line VL based on a state of thepower transmission device 1 mounted on the vehicle. The vertical line VLis orthogonal to the rotation axis X when viewed from the rotation axisX direction.

Note that a horizontal line HL in the following explanation is ahorizontal line HL based on a state of the power transmission device 1mounted on the vehicle. The horizontal line HL is orthogonal to therotation axis X when viewed from the rotation axis X direction.

In FIG. 6 , the oil catch portion 15 is formed extending further to theback side of the paper surface than the support wall portion 146.

A support base portion 151 (shelf portion) is provided at a lower edgeof the oil catch portion 15 while protruding toward the front side ofthe paper surface. The support base portion 151 is provided in a rangefrom the support wall portion 146 to the front side of the paper surfaceand from the joint portion 142 of the fourth box 14 to the back side ofthe paper surface.

The communication port 147 is provided on the vertical line VL side ofthe oil catch portion 15 (the right side in the drawing) when viewedfrom the rotation axis X direction. The communication port 147 is formedby cutting out a part of the support wall portion 146.

The communication port 147 is provided in a range that crosses thevertical line VL from the breather chamber 16 side (the right side inthe drawing) to the oil catch portion 15 side (left side in the drawing)when viewed from the rotation axis X direction.

As shown in FIG. 8 , in the present embodiment, when the vehicleequipped with the power transmission device 1 travels forward, thedifferential case 50 rotates in a counterclockwise direction CCW aroundthe rotation axis X as viewed from the third box 13 side.

Therefore, the oil catch portion 15 is positioned downstream of thedifferential case 50 in a rotational direction. A circumferential widthof the communication port 147 is wider on a left side of the verticalline VL than that on a right side. Here, a left side across the verticalline VL of the communication port 147 is a downstream side in arotational direction of the differential case 50, and the right sidethereof is an upstream side. As a result, most of the oil OL scraped upby the differential case 50 rotating around the rotation axis X can flowinto the oil catch portion 15.

Furthermore, as shown in FIG. 11 , an outer peripheral position of arotation track of the second shaft portion 446 of the pinion shaft 44and an outer peripheral position of a rotation track of thelarge-diameter gear portion 431 are offset with each other in the radialdirection of the rotation axis X. The outer peripheral position of therotation track of the second shaft portion 446 is positioned on theinner diameter side of the outer peripheral position of the rotationtrack of the large-diameter gear portion 431.

Therefore, the second shaft portion 446 has a spatial margin on theouter diameter side thereof. The oil catch portion 15 is provided usingthis space, and a space inside the main body box 10 can be effectivelyused.

As shown in FIG. 11 , the second shaft portion 446 protrudes inward ofthe small-diameter gear portion 432 when viewed from the motor 2. Aperipheral member of the second shaft portion 446 (for example, theguide portion 78 of the differential case 50 that supports the secondshaft portion 446) is positioned close to the oil catch portion 15.

As a result, the oil OL (lubricating oil) can be smoothly supplied fromthe peripheral member to the oil catch portion 15.

As shown in FIG. 7 , an end portion of the oil hole 151 a on an outerdiameter side is open inward of the support base portion 151. The oilhole 151 a extends inside the fourth box 14 to an inner diameter side.An end portion on the inner diameter side of the oil hole 151 a opens toan inner periphery of the support portion 145.

As shown in FIG. 4 , the end portion on the inner diameter side of theoil hole 151 a in the support portion 145 opens between the lip seal RSand the bearing B2.

As shown in FIGS. 8 and 11 , an oil guide 152 is mounted on the supportbase portion 151.

The oil guide 152 includes a catch portion 153 and a guide portion 154extending from the catch portion 153 to the first box 11 side (the frontside of the paper surface in FIG. 8 ).

As shown in FIG. 11 , when viewed from above, the support base portion151 is provided at a position on an outer side in the radial directionof the rotation axis X and overlapping a part of the differential case50 (the first case portion 6 and the second case portion 7), so thatinterference with the stepped pinion gear 43 (large-diameter gearportion 431) can be avoided.

The catch portion 153 is provided at a position overlapping the secondshaft portion 446 of the pinion shaft 44 when viewed from the radialdirection of the rotation axis X. Furthermore, the guide portion 154 isprovided at a position overlapping the first shaft portion 445 of thepinion shaft 44 and the large-diameter gear portion 431.

Therefore, when the differential case 50 rotates around the rotationaxis X, a part of the oil OL that is scraped up by the differential case50 moves toward the catch portion 153 and the guide portion 154.

A wall portion 153a extending in a direction away from the support baseportion 151 (upward) is provided on an outer peripheral edge of thecatch portion 153. A part of the oil OL that is scraped up by thedifferential case 50 that rotates around the rotation axis X is reservedin the oil guide 152.

A notch portion 155 is provided on the wall portion 153 a inward of thecatch portion 153 (the back side of the paper surface of FIG. 9 ).

The notch portion 155 is provided in a region facing the oil hole 151 a.A part of the oil OL reserved in the catch portion 153 is dischargedfrom the notch portion 155 toward the oil hole 151 a.

The guide portion 154 is inclined downward and away from the catchportion 153. Wall portions 154 a and 154 a are provided on both sides ofthe guide portion 154 in a width direction. The wall portions 154 a and154 a are provided over an entire length of the guide portion 154 in thelongitudinal direction. The wall portions 154 a and 154 a are connectedto a wall portion 153 a surrounding an outer periphery of the catchportion 153.

A part of the oil OL reserved in the catch portion 153 is alsodischarged to the guide portion 154 side.

As shown in FIG. 10 , the guide portion 154 extends toward the secondbox 12 at a position that avoids interference with the differential case50 (see FIG. 2 ). A tip 154 bof the guide portion 154 is positionedabove the park lock mechanism 3 (see FIG. 2 ). As indicated by an arrowin FIG. 10 , the oil OL that reaches the tip 154 b of the guide portion154 drops downward and is supplied to the park lock mechanism 3 (seeFIG. 2 ).

As shown in FIG. 2 , a radial oil passage 137 is provided between thejoint portion 132 and the wall portion 130 of the third box 13. Theradial oil passage 137 communicates with the axial oil passage 138provided inside the joint portion 132.

The axial oil passage 138 communicates with the oil reservoir portion128 provided in the lower portion of the second box 12 via thecommunication hole 112 a provided in the joint portion 112 of the firstbox 11.

The oil reservoir portion 128 penetrates the inside of the peripheralwall portion 121 in the rotation axis X direction and communicates withthe oil storage portion OP of the motor chamber Sa and the gear chamberSb.

The disk-shaped plate member 8 is provided in a direction orthogonal tothe rotation axis X in the gear chamber Sb. As described above, theplate member 8 divides the gear chamber Sb in the fourth box 14 into thefirst gear chamber Sb1 on the differential case 50 side and the secondgear chamber Sb2 on the motor 2 side.

FIGS. 12 and 13 are diagrams illustrating the plate member 8.

FIG. 12 is a plan view of the plate member 8 viewed from the motor 2side.

FIG. 13 is a schematic diagram of an A-A cross section in FIG. 12 .

As shown in FIG. 13 , the plate member 8 includes a surface 80 a and asurface 80 b. The surface 80 b faces the planetary reduction gear 4 andthe differential case 50 (see FIG. 2 ), which constitute the gearmechanism. The opposite surface 80 a (back surface) faces the motor 2(see FIG. 2 ).

As shown in FIG. 12 , the plate member 8 has a ring-shaped base portion80 when viewed from the motor 2 side. A ring-shaped support portion 801surrounding a through hole 800 is provided in a central portion of thebase portion 80.

As shown in FIG. 12 , connecting pieces 81, 82, 83, and 84 are providedon an outer peripheral edge 80 c of the base portion 80.

Each of the connecting pieces 81, 82, 83, and 84 extends outward in theradial direction from the outer peripheral edge 80 c of the base portion80. The connecting pieces 81, 82, 83 and 84 are provided with bolt holes81 a, 82 a, 83 a, and 84 a, respectively.

The connecting piece 81 is provided on an upper portion of the platemember 8 at a position that intersects with the vertical line VL. Theconnecting piece 81 extends away from the base portion 80 along thevertical line VL.

On one side (the left side in FIG. 12 ) of the vertical line VL, theconnecting pieces 82 and 83 are provided on the upper side and the lowerside of the horizontal line HL, respectively. These connecting pieces 82and 83 also extend away from the base portion 80.

The connecting piece 84 is provided on the lower side of the horizontalline HL and on the other side of the vertical line VL (the right side inFIG. 12 ). On the lower side of the horizontal line HL, the connectingpiece 84 protrudes downward from a position that passes through a loweredge of the connecting piece 83 and intersects with a straight line HLaparallel to the horizontal line HL.

The connecting piece 85 is provided on the upper side of the horizontalline HL and on the other side of the vertical line VL (the right side inFIG. 12 ). The connecting piece 85 is provided in an arc shape having awidth in the circumferential direction around the rotation axis X. Thebolt hole 85 a is provided at a position of the connecting piece 85 nearthe vertical line VL. A support pin 85 b is provided at a position nearthe horizontal line HL. The support pin 85 b protrudes toward a frontside of paper surface.

A support boss 86 for a stopper pin 861 (see FIG. 17 ) is provided onthe surface 80 a (see FIG. 13 ) of the plate member 8 on the motor 2side. The support boss 86 is provided with a hole 86 a (see FIG. 12 )through which the stopper pin 861 is inserted. The support boss 86 isprovided adjacent to the connecting piece 81 below the connecting piece81 positioned on the vertical line VL.

As shown in FIG. 12 , a mounting boss 87 is provided below the supportboss 86. The mounting boss 87 is provided at a position that intersectswith a straight line HLb that passes through the support pin 85 b and isparallel to the horizontal line HL. The mounting boss 87 protrudesfurther to the front side of paper surface than the support boss 86.

Further, a mounting boss 88 paired with the mounting boss 87 is providedbelow the support pin 85 b in the vertical line VL direction. A mountingportion 89 for a support 33, which will be described later, is providedon the opposite side (left side in the drawing) of the support pin 85 bwhen viewed from the mounting boss 87. The mounting portion 89 isprovided with two bolt holes 89 a and 89 a adjacent to each other in thehorizontal line direction.

FIG. 14 is a diagram of the fourth box 14 as viewed from the motor 2side, and is a diagram illustrating the arrangement of stepped portions148 d, 149 d, and 17 d that support the outer peripheral edge of theplate member 8.

Note that in FIG. 14 , peripheral wall portions 148 and 149 and anarcuate wall portion 17, and the stepped portions 148 d, 149 d, and 17 dare hatched in order to clarify positions thereof.

FIG. 15 is a diagram of the fourth box 14 as seen from the motor 2 side,and is a diagram illustrating a state in which the plate member 8 isattached.

As shown in FIG. 14 , the fourth box 14 is provided with the peripheralwall portions 148 and 149 when viewed from the rotation axis Xdirection. The peripheral wall portions 148 and 149 are provided on anouter diameter side of a region of the support wall portion 146 wherethe teeth portion 146 a is provided. The peripheral wall portions 148and 149 are formed in an arc shape around the rotation axis X.

The peripheral wall portion 148 is positioned below the oil catchportion 15 in the vertical line VL direction. The peripheral wallportion 148 is provided in a range that crosses the horizontal line HLpassing through the rotation axis X from the upper side to the lowerside when viewed from the rotation axis X direction. An upper endportion 148 a of the peripheral wall portion 148 is positioned near thesupport base portion 151. A lower end portion 148 b of the peripheralwall portion 148 is positioned near the straight line HLa.

An inner periphery 148 c of the peripheral wall portion 148 has an arcshape along the outer periphery of the plate member 8 (base portion 80)when viewed from the rotation axis X direction. An inner diameter of theinner periphery 148 c of the peripheral wall portion 148 is slightlylarger than the outer diameter of the plate member 8. Here, the rotationaxis X is used as a reference for the inner diameter of the innerperiphery 148 c and the outer diameter of the plate member 8.

Inside the peripheral wall portion 148, the stepped portion 148 drecessed toward the back side of paper surface is provided. When theplate member 8 is mounted to the fourth box 14, the outer peripheraledge of the plate member 8 (base portion 80) is in contact with thestepped portion 148 d from the rotation axis X direction.

Boss portions 18 each including a bolt hole 18 a are formed integrallywith the peripheral wall portion 148 on the outside of the peripheralwall portion 148. The boss portions 18 are provided near the upper endportion 148 a and the lower end portion 148 b of the peripheral wallportion 148, respectively. The boss portions 18 and 18 protrude furtherto the front side of paper surface than the peripheral wall portion 148.

The peripheral wall portion 149 is positioned below the breather chamber16. The peripheral wall portion 149 is positioned on a further back sideof paper surface than a wall portion 160 that partitions the breatherchamber 16.

An upper end portion 149 a of the peripheral wall portion 149 isconnected to the boss portion 18 on the vertical line VL as viewed fromthe rotation axis X direction. A side wall portion 159 extending towardthe oil catch portion 15 is further connected to the boss portion 18. Alower end portion 149 b of the peripheral wall portion 149 is connectedto the peripheral wall portion 141 of the fourth box 14 on the lowerside of the breather chamber 16.

An inner periphery 149 c of the peripheral wall portion 149 has an arcshape along the outer periphery of the plate member 8 (base portion 80)when viewed from the rotation axis X direction. An inner diameter of theinner periphery 149 c of the peripheral wall portion 149 is slightlylarger than the outer diameter of the plate member 8. Here, the rotationaxis X is used as a reference for the inner diameter of the innerperiphery 149 c and the outer diameter of the plate member 8.

Inside the peripheral wall portion 149, the stepped portion 149 drecessed toward the back side of paper surface is provided. When theplate member 8 is mounted to the fourth box 14, the outer peripheraledge of the plate member 8 (base portion 80) is in contact with thestepped portion 149 d from the rotation axis X direction.

The boss portions 18 and 18 each including the bolt hole 18 a are formedintegrally with the peripheral wall portion 149 on the outside of theperipheral wall portion 149. The boss portions 18 and 18 are provided atan interval in the circumferential direction around the rotation axis X.The boss portions 18 are provided on the outer periphery of the upperend portion 148 a of the peripheral wall portion 149 and on an outerperiphery of a region positioned on the lower side of the breatherchamber 16. The boss portions 18 and 18 protrude further to the frontside of paper surface than the peripheral wall portion 149.

In the fourth box 14, the arcuate wall portion 17 is provided in aregion below the breather chamber 16 and below the horizontal line HL.The arcuate wall portion 17 is provided at a position that is shifted byapproximately 180° in phase with respect to the peripheral wall portion148 in the circumferential direction around the rotation axis X.

An inner periphery 17 c of the arcuate wall portion 17 has an arc shapealong the outer periphery of the plate member 8 (base portion 80) whenviewed from the rotation axis X direction. An inner diameter of theinner periphery 17 c of the arcuate wall portion 17 is slightly largerthan the outer diameter of the plate member 8. Here, the rotation axis Xis used as a reference for the inner diameter of the inner periphery 17c and the outer diameter of the plate member 8.

The boss portion 18 including the bolt hole 18 a is formed in thearcuate wall portion 17 at a position that intersects with the straightline HLa. The boss portion 18 protrudes toward the further front side ofpaper surface than the arcuate wall portion 17.

The stepped portion 17 d is provided on the inner periphery of the bossportion 18 protruding towards the rotation axis X direction. When theplate member 8 is mounted to the fourth box 14, the outer peripheraledge of the plate member 8 (base portion 80) is in contact with thestepped portion 17 d from the rotation axis X direction.

Here, in order to mount the plate member 8 to the fourth box 14, first,the outer peripheral edge of the plate member 8 (base portion 80) isbrought into contact with the stepped portions 148 d and 149 d of theperipheral wall portions 148 and 149 and the step portion 17 d of thearcuate wall portion 17 from the rotation axis X direction.Subsequently, the plate member 8 is fixed to the fourth box 14 byscrewing bolts B passing through the bolt holes 81 a to 85 a of theconnecting pieces 81 to 85 into the corresponding bolt holes 18 a of theboss portions 18 (see FIGS. 15 and 16 ).

FIGS. 16, 17, and 18 are diagrams illustrating the park lock mechanism3. FIG. 16 is a perspective view of the fourth box 14 provided with thepark lock mechanism 3 as viewed from diagonally above. FIG. 17 is a planview of the fourth box 14 provided with the park lock mechanism 3 asviewed from the motor 2 side. FIG. 18 is a top view of the park lockmechanism 3.

As shown in FIG. 16 , the park lock mechanism 3 includes a park gear 30,a park pole 31, a park rod 32, the support 33, a holder 34, a manualplate 35, a detent spring 36, a manual shaft 37.

The park lock mechanism 3 is a park-by-wire type park lock mechanism.The park lock mechanism 3 rotates the manual shaft 37 around therotation axis Y (see FIG. 18 ) by an actuator ACT when a sensor detectsthat the vehicle equipped with the power transmission device 1 isswitched between a driving mode and a parking mode.

In the present embodiment, the park gear 30, the park pole 31, the parkrod 32, the support 33, and the holder 34 are positioned on the motor 2side of the plate member 8 (the lower side in FIG. 18 ). The manualplate 35, the detent spring 36, and the manual shaft 37 are positionedon the opposite side.

The holder 34 is a plate-like member. The holder 34 includes aprotruding portion 341 for supporting the park pole 31. As shown inFIGS. 16 and 17 , the park pole 31 is supported by the plate member 8via the holder 34.

The park pole 31 is an integral part that includes a first plate-likeportion 310 including an insertion hole 310 d and a second plate-likeportion 311 including a claw portion 311 c.

The protruding portion 341 on the holder 34 side is inserted into theinsertion hole 310 d of the park pole 31. The park pole 31 is rotatablysupported by the protruding portion 341. The park pole 31 is rotatablearound an axis line X2 parallel to the rotation axis X.

As shown in FIG. 17 , the first plate-like portion 310 extends upwardfrom a region supported by the protruding portion 341 along a straightline Lx1 orthogonal to the axis line X2 when viewed from the rotationaxis X direction.

The first plate-like portion 310 extends to a position substantially atthe same height as the support boss 86 of the plate member 8, and thenbends in a direction away from the breather chamber 16 (leftward in thedrawing).

In the first plate-like portion 310, a region ahead of the bent portion310 e extends along a straight line Lx2. A tip side of this regionserves as an operated portion 310 c that is operated by a cam 320 of thepark rod 32.

The operated portion 310 c is mounted on the cam 320 supported by thesupport 33.

The claw portion 311 c is provided below the second plate-like portion311 when viewed from the rotation axis X direction. The claw portion 311c is an engaging portion with the park gear 30. The claw portion 311 cis formed protruding from a lower portion of the second plate-likeportion 311 toward the rotation axis X side.

In the first plate-like portion 310 of the park pole 31, a locking hole310 f is provided on a side of the insertion hole 310 d. One end of aspring Sp externally inserted into the support pin 85 b of the platemember 8 is engaged with the locking hole 310 f. The park pole 31 isconstantly urged in a direction (counterclockwise direction in FIG. 17 :see the arrow) to separate the claw portion 311 c from the park gear 30by a biasing force from the spring Sp.

As shown in FIG. 3 , the first plate-like portion 310 of the park pole31 is disposed between the holder 34 and the plate member 8 in therotation axis X direction. The second plate-like portion 311 ispositioned closer to the motor 2 side (right side in the drawing) thanthe first plate-like portion 310. The second plate-like portion 311extends downward on an inner diameter side of the holder 34.

As shown in FIG. 17 , the park rod 32 is provided along a straight lineLx3 orthogonal to the rotation axis X and passing above the horizontalline HL when viewed from the rotation axis X direction.

The park rod 32 is provided such that a tip side where the cam 320 isexternally inserted faces the park pole 31 side (breather chamber 16side). The cam 320 is inserted between the support 33 and the operatedportion 310 c of the park pole 31.

When the park rod 32 is displaced in a direction (to the right side inFIG. 18 ) in which the cam 320 is pushed into between the support 33 andthe operated portion 310 c of the park pole 31, the cam 320 pushes upthe operated portion 310 c.

As a result, the park pole 31 is rotated clockwise in FIG. 17 anddisposed at an engagement position. The engaging position is a positionwhere the claw portion 311 c is engaged with an outer periphery of thepark gear 30.

When the park rod 32 is displaced in a direction (to the left side inFIG. 18 ) in which the cam 320 is pulled out from between the support 33and the operated portion 310 c of the park pole 31, the park pole 31 isrotated counterclockwise in FIG. 17 due to a biasing force of the springSp. The park pole 31 rotated in the counterclockwise direction isdisposed at a detachment position. The detachment position is a positionwhere the claw portion 311 c is detached from the outer periphery of thepark gear 30.

As shown in FIG. 18 , the other end 32 b of the park rod 32 is supportedby a connecting portion 355 of the manual plate 35. In this state, thepark rod 32 is provided so as to be displaceable in the axial directionwhile being prevented from coming off from the connecting portion 355.

The manual plate 35 includes a base portion 351, an arm portion 353, andan engaging portion 352. The base portion 351 is externally insertedinto the manual shaft 37. The arm portion 353 and the engaging portion352 extend in a radial direction of a rotation axis Y of the manualshaft 37 from an outer periphery of the base portion 351.

The base portion 351 is fixed to the manual shaft 37 in a state whererotation thereof with respect to the manual shaft 37 is restricted.

The arm portion 353 extends from the outer periphery of the base portion351 toward the motor 2. When viewed from the radial direction of therotation axis X, the arm portion 353 crosses an outer diameter side ofthe plate member 8 on the motor 2 side.

As shown in FIG. 16 , a tip side of the arm portion 353 is bent downward(to the rotation axis side), and then connected to the support portion354 including an upper surface to which the connecting portion 355 isfixed.

As shown in FIG. 18 , a base end portion 361 in the longitudinaldirection of the detent spring 36 is fixed to the fourth box 14 with thebolt B. A tip side of the detent spring 36 where a roller 365 isprovided can be elastically displaced in the radial direction of thebase portion 351 of the manual plate 35. The tip side of the detentspring 36 is in pressure contact with the outer periphery (concaveportion) of the base portion 351 of the manual plate 35.

In the embodiment, the manual shaft 37 rotates around the rotation axisY in conjunction with switching between the driving mode and the parkingmode of the vehicle equipped with the power transmission device 1.

When the manual shaft 37 rotates, the manual plate 35 fixed to themanual shaft 37 also rotates around the rotation axis Y. Then, the armportion 353 extending from the base portion 351 of the manual plate 35and the connecting portion 355 fixed to the support portion 354 at thetip of the arm portion 353 are displaced in the circumferentialdirection around the rotation axis Y. The park rod 32 connected to theconnecting portion 355 is also displaced in the longitudinal directionof the park rod 32.

As shown in FIG. 2 , the plate member 8 is interposed between the motor2 and the gear mechanism including the planetary reduction gear 4 andthe differential mechanism 5 in the rotation axis X direction (axialdirection). A strainer 90 is disposed adjacent to the plate member 8.Here, “adjacent” means that the strainer 90 is disposed near the platemember 8. The strainer 90 may be in contact with the plate member 8 ormay be spaced apart from the plate member 8. Note that FIG. 2schematically shows the strainer 90. The strainer 90 is fixed inside themain body box 10 by a fixture or the like (not shown).

FIG. 19 is an enlarged view around the strainer 90 below the main bodybox 10.

FIG. 20 is a schematic diagram showing disposition of the strainer 90when the main body box 10 is viewed from above in the verticaldirection.

As shown in FIG. 19 , the strainer 90 is disposed on the surface 80 a(facing surface) side of the plate member 8. The surface 80 a of theplate member 8 is a surface facing the motor 2 with a gap therebetweenin the rotation axis X direction. The surface 80 a is a back surface ofthe surface 80 facing the planetary reduction gear 4 and thedifferential mechanism 5 (gear mechanism). The strainer 90 is disposedoverlapping the plate member 8 in the rotation axis X direction.

The strainer 90 is disposed below the main body box 10 between the platemember 8 and the stator core 25 of the motor 2. That is, the strainer 90is disposed in the second gear chamber Sb2 and separated by the platemember 8 from the planetary reduction gear 4 and the differentialmechanism 5 disposed in the first gear chamber Sb1.

The strainer 90 includes a main body portion 91 and a suction port 92(pump inlet). The main body portion 91 is, for example, a hollowcontainer, and a filter F for filtering the oil OL is disposed inside.The suction port 92 can be, for example, a tubular member protrudingdownward from a lower surface of the main body portion 91. At least thesuction port 92 of the strainer 90 is immersed in the oil OL of the oilstorage portion OP. That is, the suction port 92 is immersed in oil. Theoil OL is introduced into the main body portion 91 through the suctionport 92. The suction port 92 of the strainer 90 is provided on the motor2 side of the main body portion 91.

As shown in FIG. 20 , the longitudinal direction of the main bodyportion 91 of the strainer 90 extends along an axis line Y1 directionthat intersects with the rotation axis X direction and is orthogonal tothe vertical direction. That is, the strainer 90 extends between themotor 2 and the gear mechanism (the planetary reduction gear 4 and thedifferential mechanism 5) in a direction (the axis line Y1 direction) toavoid interference therewith.

The main body portion 91 of the strainer 90 is disposed offset from theplanetary reduction gear 4 and the differential mechanism 5 in therotation axis X direction. The main body portion 91 of the strainer 90is positioned radially outward of the planetary reduction gear 4 and thedifferential mechanism 5, and is disposed offset from the planetaryreduction gear 4 and the differential mechanism 5 in the radialdirection of the rotation axis X. In other words, the main body portion91 of the strainer 90 does not overlap the planetary reduction gear 4and the differential mechanism 5 (gear mechanism) in the radialdirection of the rotation axis X.

As described above, the second gear chamber Sb2 in which the strainer 90is disposed communicates with the motor chamber Sa in which the motor 2is disposed through the opening 120 b. The main body portion 91 of thestrainer 90 is positioned near the coil end 251 b of the motor 2 andpositioned below the coil end 251 b in the vertical direction.

As shown in FIG. 19 , the strainer 90 is connected to a suction port 95a of an oil pump 95 (pump) provided outside the main body box 10 via apipe PI. For example, an electric oil pump driven by a motor (not shown)can be used as the oil pump 95.

A discharge port 95 b of the oil pump 95 is connected to oil holes Ha,Hb, and Hc (see FIG. 2 ) formed in the upper portion of the main bodybox 10 via a pipe, an oil passage, or the like (not shown) disposedinside the vehicle. The oil hole Ha is formed on an upper portion of thefourth box 14 and on the outer diameter side of the differential case50. The oil hole Hb is formed on an upper portion of the second box 12and on the outer diameter side of the coil end 251 b of the motor 2. Theoil hole Hc is formed on an upper portion of the third box 13 and nearthe coil end 253 a of the motor 2.

Functions of the power transmission device 1 having such a configurationwill be described.

As shown in FIG. 1 , in the power transmission device 1, the planetaryreduction gear 4, the differential mechanism 5 and the drive shafts DAand DB are arranged along the transmission path of the output rotationof the motor 2.

When the motor 2 is driven and the rotor core 21 rotates around therotation axis X, the rotation is input to the sun gear 41 of theplanetary reduction gear 4 via the motor shaft 20 that rotates togetherwith the rotor core 21.

As shown in FIG. 3 , in the planetary reduction gear 4, the sun gear 41serves as an input unit for the output rotation of the motor 2. Thedifferential case 50 that supports the stepped pinion gear 43 serves asan output unit for the input rotation.

When the sun gear 41 rotates around the rotation axis X due to the inputrotation, the stepped pinion gear 43 (the large-diameter gear portion431 and the small-diameter gear portion 432) rotates around the axisline X1 due to the rotation input from the sun gear 41 side.

Here, the small-diameter gear portion 432 of the stepped pinion gear 43meshes with the ring gear 42 fixed to the inner periphery of the fourthbox 14. Therefore, the stepped pinion gear 43 revolves around therotation axis X while rotating around the axis line X1.

Here, in the stepped pinion gear 43, the outer diameter R2 of thesmall-diameter gear portion 432 is smaller than the outer diameter R1 ofthe large-diameter gear portion 431 (see FIG. 3 ).

As a result, the differential case 50 (the first case portion 6 and thesecond case portion 7) that supports the stepped pinion gear 43 rotatesaround the rotation axis X at a rotation speed lower than that of therotation input from the motor 2 side.

Therefore, the speed of the rotation input to the sun gear 41 of theplanetary reduction gear 4 is greatly reduced by the stepped pinion gear43. The speed-reduced rotation is output to the differential case 50(differential mechanism 5).

Then, when the differential case 50 rotates around the rotation axis Xdue to the input rotation, the drive shafts DA and DB meshing with thepinion mate gear 52 rotate around the rotation axis X within thedifferential case 50. As a result, the left and right driving wheels(not shown) of the vehicle equipped with the power transmission device 1are rotated by the transmitted rotational driving force.

As shown in FIG. 2 , inside the motor chamber Sa and the gear chamberSb, there is formed the oil storage portion OP in which the oil OL forlubricating is stored. The oil OL stored in the oil storage portion OPis scraped up by the rotation of the motor 2 and cools the motor 2. Apart of the oil OL that is scraped up also flows into the internal spaceSc through the opening 136 a of the connection wall 136 to lubricate thebearings B1 and B4.

In the gear chamber Sb, the oil OL stored in the oil storage portion OPis scraped up by the differential case 50 rotating around the rotationaxis X when the output rotation of the motor 2 is transmitted.

The scraped up oil OL lubricates a meshing portion between the sun gear41 and the large-diameter gear portion 431, a meshing portion betweenthe small-diameter gear portion 432 and the ring gear 42, and a meshingportion between the pinion mate gear 52 and the side gears 54A and 54B.

As shown in FIG. 8 , the differential case 50 rotates around therotation axis X in the counterclockwise direction CCW when viewed fromthe third box 13 side.

The oil catch portion 15 is provided on the upper portion of the fourthbox 14. The oil catch portion 15 is positioned downstream of therotational direction of the differential case 50. Most of the oil OLscraped up by the differential case 50 flows into the oil catch portion15 and is supplied to the oil guide 152 placed on the support baseportion 151 inside the oil catch portion 15. As shown in FIG. 10 , apart of the oil OL supplied to the oil guide 152 drops from the tip 154b and lubricates the park gear 30 and the like (see FIG. 3 ) of the parklock mechanism 3 positioned below.

In this way, most of the oil OL scraped up by the differential case 50flows into the oil catch portion 15, but the oil OL that falls due togravity returns to the oil storage portion OP and is stored therein. Apart of the oil OL stored in the oil storage portion OP flows into theoil reservoir portion 128 according to gravity. Although the temperatureof the oil OL rises due to the motor 2 and the scraping up of thedifferential case 50, the oil OL flows into the oil reservoir portion128 and is cooled by the coolant CL flowing through the cooling path CP.

As shown in FIG. 19 , the strainer 90 is disposed in the oil storageportion OP within the second gear chamber Sb2.

When the oil pump 95 is driven, the oil OL in the oil storage portion OPis sucked through the suction port 92 of the strainer 90. The oil OLintroduced into the main body portion 91 of the strainer 90 passesthrough the filter F to filter out impurities. The filtered oil OL issucked into the suction port 95 a of the oil pump 95 via the pipe PI anddischarged from the discharge port 95 b.

The oil OL discharged from the discharge port 95 b is supplied to theoil holes Ha, Hb, and Hc (see FIG. 2 ) inside the main body box 10. Theoil OL supplied to the oil hole Ha is supplied to the planetaryreduction gear 4 in the fourth box 14, the differential case 50, and thelike. The oil OL supplied to the oil hole Hb is supplied to the coil end253 b side of the motor 2 and the park lock mechanism 3. The oil OLsupplied to the oil hole Hc is supplied to the coil end 253 a side ofthe motor 2. Thus, the power transmission device 1 has a mechanism forfiltering and circulating the oil OL used for lubricating and coolingeach component.

As shown in FIG. 19 , the planetary reduction gear 4 and thedifferential mechanism 5 are arranged to face the surface 80 b of theplate member 8 in the rotation axis X direction.

The suction port 95 a of the strainer 90 is disposed adjacent to theplate member 8 on the surface 80 a side, which is the facing surfacefacing the surface 80 b of the plate member 8.

That is, the suction port 95 a of the strainer 90 is disposed in a space(second gear chamber Sb2) separated from a space (first gear chamberSb1) in which the planetary reduction gear 4 and the differentialmechanism 5, which constitute a gear mechanism, are disposed.

Here, when the strainer 90 is disposed in the oil storage portion OP inthe first gear chamber Sb1, the suction port 92 of the strainer 90 ispositioned near the differential case 50. When the differential case 50rotates to scrape up the oil OL in the oil storage portion OP, theamount of oil near the differential case 50 may decrease. When the oilpump 95 operates in this state, the suction port 92 of the strainer 90may suck air, which may affect suction performance of the oil pump 95.

In the embodiment, the first gear chamber Sb1 and the second gearchamber Sb2 are adjacent to each other but separated by the plate member8. Therefore, although the strainer 90 of the second gear chamber Sb2 ispositioned near the differential case 50, even if the differential case50 scrapes up the oil OL, the amount of oil near the suction port 92 ofthe strainer 90 is less likely to be affected. Therefore, it is possibleto reduce the intake of air by the suction port 92.

Since the strainer 90 is disposed offset with respect to thedifferential case 50 in the rotation axis X direction and in the radialdirection of the rotation axis X, the influence of the oil OL beingscraped up by the differential case 50 can be further reduced. Thestrainer 90 can be prevented from interfering with the differential case50, which is a rotating body.

The second gear chamber Sb2 in which the strainer 90 is disposed and themotor chamber Sa communicate with each other through the opening 120 bof the beam portion 120. The oil OL warmed by the stator core 25 of themotor 2, which is a heat source, is discharged from the opening 120 b(outlet) and stored in the oil storage portion OP of the second gearchamber Sb2. Therefore, the suction port 92 of the strainer 90positioned in the second gear chamber Sb2 easily sucks the oil OL warmedby the stator core 25. At a low temperature, viscosity of the oil OLtends to increase. By disposing the suction port 92 of the strainer 90near the motor 2, increase in the viscosity of the oil OL near thesuction port 92 can be reduced even at a low temperature, and thesuction performance of the oil pump 95 can be improved.

The strainer 90 is positioned near the coil end 251 b of the motor 2 andpositioned below the coil end 251 b in the vertical direction.Therefore, the oil OL warmed by the coil end 251 b tends to move towardthe strainer 90 side due to gravity.

As described above, the power transmission device 1 according to theembodiment has the following configuration.

(1) The power transmission device 1 includes:

-   -   the motor 2;    -   the planetary reduction gear 4 and the differential mechanism 5        (gear mechanism) connected downstream of the motor 2;    -   the drive shaft DA (drive shaft) connected downstream of the        planetary reduction gear 4 and the differential mechanism 5        (gear mechanism) and disposed passing through the inner        periphery of the motor 2;    -   the oil pump 95 (pump) that sucks the oil OL through the suction        portion 92 (pump inlet) of the strainer 90; and    -   the plate member 8 (plate) including the surface 80 b (facing        surface) facing the planetary reduction gear 4 and the        differential mechanism 5 (gear mechanism) in the rotation axis X        direction (axial direction).

The suction port 92 (pump inlet) of the strainer 90 is disposed adjacentto the plate member 8 (plate) on the surface 80 a side (a back surfaceof the facing surface).

The plate member 8 separates the space in which the planetary reductiongear 4 and the differential mechanism 5 (gear mechanism) are disposedfrom the space in which the suction port 92 (pump inlet) of the strainer90 is disposed. As a result, it is possible to reduce decrease in theamount of oil near the suction port 92 due to scraping up by thedifferential case 50, and it is possible to reduce the air suction ofthe oil pump 95.

Incidentally, the power transmission device 1 including the drive shaftDA (drive shaft) penetrating the inner periphery of the motor 2 has anadvantage of reducing expansion in the radial direction.

Here, when separating the space for the gear mechanism and the pumpinlet, as a comparative method, for example, a separate chamber may beprovided on the outer periphery of the main body box 10 and the pumpinlet may be disposed in the separate chamber.

However, in this comparative method, the power transmission device 1tends to expand in the radial direction of the rotation axis X, and theadvantage of the configuration in which the drive shaft DA is disposedpassing through the inner periphery of the motor 2 tends to bediminished. On the other hand, in the embodiment, the method of theembodiment in which the space is separated by the plate member 8 canreduce the decrease in the amount of oil near the suction port 92 whileutilizing the advantage of the configuration in which the drive shaft DAis disposed passing through the inner periphery of the motor 2.

The “pump inlet” is in contact with the reserved oil, that is, isimmersed in the reserved oil and is connected to the suction port 95 aof the oil pump 95. As in the embodiment, when the strainer 90 isconnected to the suction port 95 a of the oil pump 95, the suctionportion 92 of the strainer 90 corresponds to the “pump inlet”. Forexample, when the suction port 95 a of the oil pump 95 is in directcontact with (immersed in) the reserved oil, the suction port 95 a ofthe oil pump 95 corresponds to the “pump inlet”. This case will beexplained in Modification 1 below.

The “gear mechanism” is the entire mechanism including gears. Forexample, in the case of the embodiment, the gear mechanism includes theplanetary reduction gear 4 and the differential mechanism 5(differential gear).

“Connected downstream” means a connection relation in which power istransmitted from a component disposed upstream to a component positioneddownstream. For example, the “planetary reduction gear 4 connecteddownstream of the motor 2” means that power is transmitted from themotor 2 to the planetary reduction gear 4.

Note that, for example, the gear mechanism may be connected downstreamof the motor 2 via a transmission mechanism, a clutch, or the like. Inthis case, the connection relation is such that the power of the motor 2is transmitted to the gear mechanism via the transmission mechanism, theclutch, or the like. The transmission mechanism is a mechanism having atransmission function, and includes, for example, a stepped transmissionmechanism and a continuously variable transmission mechanism.

The “power transmission device” is a power train device (transmission,speed reducer, or the like) equipped with a rotating electric machine.

(2) The plate member 8 (plate) is interposed between the motor 2 and theplanetary reduction gear 4 and the differential mechanism 5 (gearmechanism) in the rotation axis X direction (axial direction).

With this configuration, the plate member 8 is disposed on the motor 2side with respect to the planetary reduction gear 4 and the differentialmechanism 5, and the suction port 92 of the strainer 90 is disposedbetween the motor 2 and the plate member 8. That is, since the suctionport 92 (pump inlet) is disposed at a position near the motor 2 servingas a heat source, the oil OL around the suction port 92 is warmed by themotor 2. Therefore, it is easy for the oil pump 95 to suck the oil OLeven at a low temperature under which the viscosity of the oil OL tendsto increase, and the suction performance of the oil pump 95 can beimproved.

(3) The pump inlet is configured as the suction port 92 of the strainer90.

By including the strainer 90 in the power transmission device 1, avolume of the oil OL to be filtered can be increased according to avolume of the strainer 90. Therefore, it is easy to adjust a dischargeamount of the oil OL from the oil pump 95, so that the powertransmission device 1 can provide an efficient circulation mechanism forthe oil OL.

(4) The longitudinal direction of the main body portion 91 of thestrainer 90 intersects with the rotation axis X direction (axialdirection) of the motor 2.

By configuring in this way, it is possible to reduce the increase in thesize of the power transmission device 1 in the rotation axis X directionwhile ensuring a volume of the main body portion 91.

(5) The main body portion 91 of the strainer 90 does not overlap theplanetary reduction gear 4 and the differential mechanism 5 (gearmechanism) in the radial direction of the rotation axis X (radialdirection).

Since the main body portion 91 of the strainer 90 does not overlap theplanetary reduction gear 4 and the differential mechanism 5,interference with the planetary reduction gear 4 and the differentialmechanism 5, which are rotating bodies, can be reduced.

(6) The power transmission device 1 includes the bearing B3 (bearing)supported by the plate member 8 (plate).

The planetary reduction gear 4 and the differential mechanism 5 (gearmechanism) are supported by the plate member 8 (plate) via the bearingB3 (bearing).

Specifically, the outer periphery of the cylindrical wall portion 611 ofthe first case portion 6 of the differential case 50 is supported by theplate member 8 via the bearing B3. By giving the plate member 8 thefunction of supporting the bearing B3, there is no need to provideanother member for supporting the bearing B3, and the number of parts ofthe power transmission device 1 can be reduced. That is, there is noneed to provide another member for supporting the bearing.

(7) The power transmission device 1 includes the park pole 31 supportedby the plate member 8 (plate).

By giving the plate member 8 the function of supporting the park pole 31of the park lock mechanism 3, there is no need to provide another memberfor supporting the park pole 31, and the number of parts of the powertransmission device 1 can be reduced.

(8) The gear mechanism includes the planetary reduction gear 4.

As described above, the gear mechanism means the entire mechanismincluding gears, and in the embodiment, the planetary reduction gear 4is included as the gear mechanism.

(Modification 1)

FIG. 21 is a diagram showing disposition of the strainer 90 according toModification 1.

FIG. 22 is a schematic diagram showing disposition of the strainer 90when the main body box 10 is viewed from above in the verticaldirection.

As described above, in the embodiment, the strainer 90 is disposedbetween the planetary reduction gear 4 and the differential mechanism 5and the motor 2 (see FIG. 19 ). The longitudinal direction of the mainbody portion 91 of the strainer 90 extends in the axis line Y1 directionintersecting with the rotation axis X (see FIG. 20 ).

In Modification 1, as shown in FIG. 21 , the strainer 90 is disposed inthe oil reservoir portion 128 provided below the motor chamber Sa. Thesuction port 92 is positioned near the second gear chamber Sb2 in theoil reservoir portion 128.

The main body portion 91 of the strainer 90 overlaps the motor 2 on theouter side in the radial direction of the rotation axis X on the lowerside of the motor 2. As shown in FIG. 22 , the main body portion 91 isseparated from the planetary reduction gear 4 and the differentialmechanism 5 by the plate member 8. The main body portion 91 does notoverlap the planetary reduction gear 4 and the differential mechanism 5in the radial direction of the rotation axis X. As a result, as in theembodiment, it is possible to reduce the decrease in the amount of oilnear the suction port 92 due to scraping up of the oil OL, and it ispossible to reduce the air suction of the oil pump 95.

As shown in FIG. 22 , in Modification 1, the longitudinal direction ofthe main body portion 91 of the strainer 90 extends along the rotationaxis X direction.

In this way, in Modification 1, by disposing the main body portion 91 ofthe strainer 90 to be slid onto the outer periphery (outer side in theradial direction) of the motor 2, the expansion of the powertransmission device 1 in the rotation axis X direction is reduced. Inthis case, the volume of the strainer 90 can be ensured by extending thelongitudinal direction of the main body portion 91 in the rotation axisX direction.

Note that in the example shown in FIG. 21 , the main body portion 91extends to a position overlapping not only the stator core 25 of themotor 2 but also the rotor core 21, but the present invention is notlimited thereto. The main body portion 91 may be disposed, for example,extending to a position overlapping at least the stator core 25.

The oil OL used for cooling and lubricating the motor 2 is dischargedfrom the opening 120 b. A part of the discharged oil OL flows into theoil reservoir portion 128 through the second gear chamber Sb2.Therefore, in Modification 1, the oil OL warmed by the motor 2, which isa heat source, is sucked into the suction port 92 of the strainer,similarly to the embodiment. Therefore, in Modification 1, it is alsoeasy for the oil pump 95 to suck the oil OL even at a low temperatureunder which the viscosity of the oil OL tends to increase, and dischargeperformance of the oil pump 95 can be improved.

As described above, the power transmission device 1 of Modification 1has the following configuration.

(9) The motor 2 includes the rotor core 21 (rotor) and the stator core25 (stator) positioned on the outer side of the radial direction (radialdirection) the rotation axis X of the rotor core 21 (rotor).

The main body portion 91 of the strainer 90 overlaps the motor 2 on theouter side of the radial direction (radial direction) the rotation axisX.

By disposing the main body portion 91 of the strainer 90 to be slid ontothe outer periphery of the motor 2, the expansion of the powertransmission device 1 in the rotation axis X direction is reduced.

(10) The main body portion 91 of the strainer 90 overlaps the rotor core21 (rotor) motor 2 on the outer side of the radial direction (radialdirection) the rotation axis X.

By expanding the main body portion 91 of the strainer 90 so as tooverlap not only the outer periphery of the stator core 25 of the motor2 but also the outer periphery of the rotor core 21, the volume of thestrainer 90 can be increased and performance of filtering the oil OL canbe improved.

(Modification 2)

FIG. 23 is a schematic diagram showing disposition of the strainer 90according to Modification 2.

As shown in FIG. 23 , in Modification 2, a plate member 900 is providedseparately from the plate member 8 disposed between the planetaryreduction gear 4 and the differential mechanism 5 and the motor 2, andthe strainer 90 is disposed adjacent to this plate member 900.

The plate member 900 is disposed on the opposite side of the planetaryreduction gear 4 and the differential mechanism 5 to the plate member 8.A surface 900 a of the plate member 900 faces the planetary reductiongear 4 and the differential case 50. The strainer 90 is disposed on asurface 900 b side, which is a surface on a back side of the surface 900a. Similar to the embodiment, the strainer 90 is connected to the oilpump 95 via the pipe PI or the like.

The oil storage portion OP is also formed in the space on the surface900 b side inside the main body box 10, and the suction port 92 of thestrainer 90 is immersed in oil. By operating the oil pump 95, thesuction port 92 sucks the oil OL.

In Modification 2, the plate member 900 also separates the space inwhich the planetary reduction gear 4 and the differential mechanism 5,which constitute a gear mechanism, are disposed, and the space in whichthe suction port 92 of the strainer 90, which is the pump inlet, isdisposed. The main body portion 91 of the strainer 90 does not overlapthe planetary reduction gear 4 and the differential mechanism 5 in theradial direction of the rotation axis X.

Therefore, in Modification 2, the decrease in the amount of oil near thesuction port 92 of the strainer 90 due to the scraping up by thedifferential case 50 of the differential mechanism 5 is reduced,similarly to the embodiment. As a result, the air suction of the oilpump 95 can be reduced.

(Modification 3)

FIGS. 24 to 26 are diagrams showing a configuration example of the oilpump 95 according to Modification 3.

In the embodiment, in the power transmission device 1, an example inwhich the mechanism for filtering and circulating the oil OL isconstituted by the oil pump 95 and the strainer 90, is described (seeFIG. 2 ). However, the circulation mechanism for the oil OL is notlimited to the example in the embodiment, and may be configured withoutthe strainer 90, for example.

As shown in FIG. 24 , when the strainer is omitted, the filter F forfiltering impurities may be disposed inside the pipe PI connected to thesuction port 95 a of the oil pump 95.

In the case of FIG. 25 , when the oil pump 95 is driven, the oil OL issucked from the end portion PE of the pipe PI, passes through the filterF, and is sucked into the suction port 95 a of the oil pump 95. That is,the end portion PE of the pipe PI corresponds to the “pump inlet”.

FIG. 25 also shows an example in which the end portion PE of the pipe PIcorresponds to the “pump inlet” as in FIG. 24 , but in FIG. 25 , the endportion PE of the pipe PI is expanded in diameter, and the filter F isdisposed at the end portion PE. By configuring as shown in FIG. 25 , thesize of the filter F can be increased.

When applying the configurations of FIGS. 24 and 25 to the embodiment,for example, the oil pump 95 and the pipe PI may be disposed in thesecond gear chamber Sb2 (see FIG. 19 ). Alternatively, only a part ofthe pipe PI including the end portion PE may be disposed in the secondgear chamber Sb2, and the oil pump 95 may be disposed outside the mainbody box 10.

FIG. 26 shows an example in which the pipe is also omitted, and thefilter F that filters the oil OL is disposed directly at the suctionport 95 a of the oil pump 95. When applying this configuration to theembodiment, the oil pump 95 can be disposed in the second gear chamberSb2 (see FIG. 19 ).

The configurations of FIGS. 24 to 26 can be applied not only to theembodiment but also to Modifications 1 and 2.

When applied to Modification 1 (see FIG. 21 ), the oil pump 95 and thepipe PI may be disposed in the oil reservoir portion 128. Alternatively,only a part of the pipe PI including the end portion PE may be disposedin the oil reservoir portion 128, and the oil pump 95 may be disposedoutside the main body box 10.

When applied to Modification 2 (see FIG. 23 ), the oil pump 95 and thepipe PI may be disposed on the surface 900 b side of the plate member900 inside the main body box 10. Alternatively, only a part of the pipePI including the end portion PE may be disposed on the surface 900 bside of the plate member 900, and the oil pump 95 may be disposedoutside the main body box 10.

(Other Modifications)

Although an example using an electric oil pump as the oil pump 95 isdescribed in the embodiment, a mechanical oil pump may be used. Forexample, the mechanical oil pump may be disposed in the motor chamber Saof the main body box 10 and driven using the rotation of the motor 2.

Although the embodiment of the present invention has been describedabove, the above embodiment merely exemplifies one application exampleof the present invention, and does not intend to limit the technicalscope of the present invention to the specific configuration of theabove embodiment.

REFERENCE SIGNS LIST

1: power transmission device

2: motor

4: planetary reduction gear (gear mechanism)

5: differential mechanism (gear mechanism)

8, 900: plate member (plate)

8 a: surface (facing surface)

8 b: surface (back surface of facing surface)

90: strainer

91: main body portion

92: suction port (pump inlet)

95: oil pump (pump)

DA, DB: drive shaft (drive shaft)

B3: bearing (bearing)

1. A power transmission device, comprising: a motor; a gear mechanism connected downstream of the motor; a drive shaft connected downstream of the gear mechanism and disposed passing through an inner periphery of the motor; a pump that sucks oil through a pump inlet; and a plate that includes a facing surface facing the gear mechanism in an axial direction, wherein the pump inlet is disposed adjacent to the plate on a back surface side of the facing surface.
 2. The power transmission device according to claim 1, wherein the plate is interposed between the motor and the gear mechanism in the axial direction.
 3. The power transmission device according to claim 1, wherein the pump inlet serves as a suction port of a strainer.
 4. The power transmission device according to claim 3, wherein a longitudinal direction of a main body portion of the strainer intersects with an axial direction of the motor.
 5. The power transmission device according to claim 3, wherein the motor includes a rotor and a stator positioned on an outer side in a radial direction of the rotor, and a main body portion of the strainer overlaps the motor on the outer side in the radial direction.
 6. The power transmission device according to claim 5, wherein the main body portion of the strainer overlaps the rotor of the motor on the outer side in the radial direction.
 7. The power transmission device according to claim 5, wherein the main body portion of the strainer does not overlap the gear mechanism in the radial direction.
 8. The power transmission device according to claim 1, further comprising: a bearing supported by the plate, wherein the gear mechanism is supported by the plate via the bearing.
 9. The power transmission device according to claim 1, further comprising: a park pole supported by the plate.
 10. The power transmission device according to claim 1, wherein the gear mechanism includes a planetary reduction gear. 